text: Brevetoxin (PbTx), or brevetoxins, are a suite of cyclic polyether compounds produced naturally by a species of dinoflagellate known as Karenia brevis.  Brevetoxins are neurotoxins that bind to voltage-gated sodium channels in nerve cells, leading to disruption of normal neurological processes and causing the illness clinically described as neurotoxic shellfish poisoning (NSP).
  Although brevetoxins are most well-studied in K. brevis, they are also found in other species of Karenia and at least one large fish kill has been traced to brevetoxins in Chattonella.
  Other Brevetoxins:
  *Brevetoxin-5 (PbTx-5): like PbTx-2, but acetylated hydroxyl group in position 38.
  *Brevetoxin-6 (PbTx-6): like PbTx-2, but double bond 27-28 is epoxidated.
  Brevetoxin-B was synthesized in 1995 by K. C. Nicolaou and coworkers in 123 steps with 91% average yield (final yield ~9·10) and in 2004 in a total of 90 steps with an average 93% yield for each step (0.14% overall).
  K. C. Nicolaou and coworkers reported their synthesis of Brevetoxin-1 in 1998. In 2009, Michael Crimmins and co-workers reported their synthesis of Brevetoxin-1 as well.